Simplify the following expression: ${-3(5r-7)+2(-1-2r)}$
Answer: Distribute the ${-3}$ into the first set of parentheses: $ {-3(}\gray{5r-7}{)} + 2(-1-2r) $ $ {-15r+21} + 2(-1-2r) $ Distribute the ${2}$ into the parentheses: $ -15r+21 + {2(}\gray{-1-2r}{)} $ $ -15r+21 {-2-4r} $ Rewrite the expression to group the ${r}$ terms and numeric terms: $ {-15r - 4r} + {21 - 2}$ Combine the ${r}$ terms: $ {-19r} + {21 - 2}$ Combine the numeric terms: $ {-19r} + {19}$ The simplified expression is $-19r+19$